G.S. · Geological Survey · M G*** · M S.
| title | ISBN-13 (ISBN-10) | year of publication |
|---|---|---|
| Allegany County | 978-1-146-18235-5 (1-146-18235-X) | 2010 |
| Cecil County | 978-1-143-05475-4 (1-143-05475-X) | 2010 |
| Maryland Geological Survey, Volume 6, part 1 | 978-1-143-31042-3 (1-143-31042-X) | 2010 |